Sixth Taste Discovered

Spoiler alert! He's been dead the whole time. Oops, wrong "Sixth." We're talking taste, not sense. Move over "yumminess," all the in-the-know tongues have moved on from the fifth taste, umami, to the sixth taste: kokumi.

Advertisement - Continue Reading Below

Japanese researchers at Ajinomoto, a seasoning and food product company, have published their findings about kokumi in the Journal of Biological Chemistry. More of a sensation than a taste, it is a food or flavor that enhances sweet, salty and umami tastes. They discovered our tongues have receptors not only for salty, sweet, bitter and sour flavors, but also for calcium. When activated, these receptors enhance other flavors when kokumi is detected. Sometimes translated as "heartiness" or mouthfulness, kokumi can be created by slow cooking stocks, curing, drying, roasting, searing, confiting or braising meat.

Most Popular

The compounds that create kokumi include calcium, protamine (which can be found in milt or fish sperm), L-histidine and glutathione, which is present in yeast extract. Tests have, unfortunately, not involved slow-braised pork shoulder or seared beef but flavored water. Scientists created synthetic calcium-like compounds and tested how well they activated calcium channels. They then diluted those substances in differently salt water, sugar water and other flavored waters and asked their panel of discriminating tasters to rate the strength of the flavors. Results showed promise. The compounds that created higher activity in the calcium receptors also caused flavors to be more optimally enhanced. Scientists are choosing to, for the time being, using their discovery for good. They are using it to attempt to create healthier food that is lower in salt and sugar, but still actually tastes good.

The problem at present is finding out how to activate the calcium receptors with supplements other than calcium, which only seems to taste good when it combines with fat in foods like cheese and butter. So scientists are considering ways in which to tweak calcium so that its flavor improves. Until then, it's back to the slow cooker and fish sperm.